Cleaning the flask with alcohol, Perkin noticed purple portions of the solution. In one attempt, Perkin oxidized aniline using potassium dichromate, whose toluidine impurities reacted with the aniline and yielded a black solid, suggesting a "failed" organic synthesis. In 1856, William Henry Perkin, then age 18, was given a challenge by his professor, August Wilhelm von Hofmann, to synthesize quinine. In 2007, two more were isolated and identified: mauveine B2, an isomer of mauveine B with methyl on different aryl group, and mauveine C, which has one more p-methyl group than mauveine A. The molecular structure of mauveine proved difficult to determine, finally being identified in 1994. In fact, safranine is a 2,8-dimethyl phenazinium salt, whereas the parasafranine produced by Perkin is presumed to be the 1,8- (or 2,9-) dimethyl isomer. In 1879, Perkin showed mauveine B related to safranines by oxidative/ reductive loss of the p-tolyl group. Mauveine B ( C 27H 25N + 4X −) incorporates one molecule each of aniline, p-toluidine, and two of o-toluidine. Mauveine A ( C 26H 23N + 4X −) incorporates 2 molecules of aniline, one of p-toluidine, and one of o-toluidine. Its organic synthesis involves dissolving aniline, p-toluidine, and o-toluidine in sulfuric acid and water in a roughly 1:1:2 ratio, then adding potassium dichromate. Mauveine is a mixture of four related aromatic compounds differing in number and placement of methyl groups. It is also among the first chemical dyes to have been mass-produced. It was discovered serendipitously by William Henry Perkin in 1856 while he was attempting to synthesise the phytochemical quinine for the treatment of malaria. Mauveine, also known as aniline purple and Perkin's mauve, was one of the first synthetic dyes. Letter from Perkin's son, with a sample of dyed silk
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